Computing and statistical data analysis: remote login info

There are a number of ways to log in to the RHUL linux cluster. Hopefully one of the options below will work for you.

Logging into linappserv1:

Once you have access to a unix environment (e.g. using one of the methods below), from the unix prompt type:

ssh -X username@linappserv1.pp.rhul.ac.uk

where of course you put your username before the @. Remember that everything is case sensitive. You will be prompted for your password. If this works you should get a prompt that looks like:

[linappserv1]~>

And you're in! To exit, type exit. Now to get access to a unix environment in the first place, try one of the methods below.

From the RHUL teaching lab using cygwin:

The first bench of computers in the RHUL teaching lab (closest to the door) should have cygwin installed (but as of 19 Oct this was only on the far side of the first bench, 2nd computer from the left).
  • From the start menu go to Academic applications -> Physics -> RXvt -> shortcut to startxwin.bat, as shown here. You will see an "X" appear in the task bar. (If a terminal window opens up, just close it.)
  • From the same menu, select this time Rxvt. This will open up a terminal window.
  • Login to linappserv1 using: ssh -X linappserv1.pp.rhul.ac.uk (I think -Y does essentially the same as -X. Either of these allows you to open up a separate X-window once you're logged in.)
  • You're in! To test that an x-window can be sent back to you, try starting a x-based application, e.g., type: xclock &

    • From the RHUL teaching lab using Exceed:

    NB This no longer appears to work from RHUL -- please use cygwin

    Most of computers in the RHUL teaching lab except the ones on the bench closest to the door should have Exceed installed.

  • Start Exceed by going from the start menu to Current applications -> Hummingbird Connectivity -> Exceed -> Exceed. Exceed will start and display its logo, and maybe a toolbar that you can ignore (or close).
  • Start Putty by going to Current Applications -> Putty -> Putty. This will bring up the PuTTY configuration window.
  • From the column on the left under SSH, click on X11. Then click the box next to "Enable X11 forwarding" as shown here.
  • From the top of the column on the left, click on Session. Enter for the host name linappserv1.pp.rhul.ac.uk as shown here. The protocol SSH should be selected.
  • Click on Open. This should bring up a terminal window on linappserv1 where you can log in. If it asks you to accept some security warning, click on "yes" to do so. As mentioned above you can test that the x-windows can be sent back by starting an x-based application, e.g., type: xclock &

    • From UCL using Exceed:

    I am told this is also possible and the instructions are probably similar to above. Could one of the UCL students please send an update if needed.

    Using Xming on your own computer:

    You can download and install the x-windows server Xming on your own PC (with Windows XP/2003/Vista). It is available free here. This allows you to open an x-window and from there to login to other unix machines using ssh. I have yet to test this one personally but it appears to be a superior solution to installing cygwin (below). If anyone gets this to work please let us know how it goes. It should be enough to install xming-font, ssh and either putty or x-ming-portable-putty (I think).

    Note that the main difference between Xming and cygwin is that cygwin provides a complete emulated unix environment on a windows computer. This is nice but for us it's not necessary. Xming will simply allow you to create e.g. an x-windows terminal window (an xterm) and from there you connect to another linux machine with ssh.

    Using cygwin on your own computer:

    You can download and install the x-windows version of cygwin from here. I've copied some more information on how to install it into the file here. (Or if this doesn't work the older version of the notes is here.) The x-windows version of cygwin appears as of Oct 08 to be no longer maintained. If there are difficulties with this then Xming (above) could be a better solution.

    From a Macintosh:

    My understanding is that it's easy to bring up an xterm from Mac OS and from there you can use ssh. I'm looking for details on this (if anyone has details please let me know).

    Transfering files to linappserv1:

    For some of the course exercises it may be necessary to download files from the web and then to transfer these files to the RHUL linux cluster, linappserv1.pp.rhul.ac.uk.

    First a warning: when you download a text file, e.g., a C++ source file, from the web to a Windows machine, Windows may place the suffice ".txt" on the end. You don't want this and if it gets put on you should rename the file to get rid of the .txt suffix.

    To transfer files from a PC to linappserv1 you can use the program ftp or one of its variants (sftp, psftp, WinSCP3). From RHUL the following appears to work:

  • From the teaching lab PC, right-click on the folder (or file) that you want to transfer; select "send to", then select "WinSCP3 (uploading using SFTP or SCP)". This will bring up a window with a bunch of fields to fill in.
  • Enter the host name linappserv1.pp.rhul.ac.uk, your username and password. Accept the other default settings and click on "login".
  • If a window appears asking whether you want to trust the remote computer, answer yes ("accept host key" or similar).
  • Another window will appear asking where you want the files to go -- you can either accept the default or supply a new target destination.
    • It should also be possible to use psftp via PUTTY; but from the RHUL computers I couldn't get this to work. If anyone has better luck with this please let us know.

    Update -- thanks to Andy for the following recipes using OpenSSH's secure copy, SCP (substitute your username appropriately):

    scp myfile username@linappserv1.pp.rhul.ac.uk:/home/username/

    or to transfer from the server back to my laptop:

    scp username@linappserv1.pp.rhul.ac.uk:/home/username/myfile ./

    This works on Mac OSX, Ubuntu Linux and on Windows. WinSCP is available here:

    http://winscp.net/eng/index.php

    It comes with OSX and Linux as standard. You can transfer entire directories too. To the server:

    scp -r myfolder username@linappserv1.pp.rhul.ac.uk:/home/username

    From the server:

    scp -r username@linappserv1.pp.rhul.ac.uk:/home/username ./

    Glen Cowan